High allelic diversity in the methyltransferase gene of a phase variable type III restriction-modification system has implications for the fitness of Haemophilus influenzae

Phase variable restriction-modification (R-M) systems are widespread in Eubacteria. Haemophilus influenzae encodes a phase variable homolog of Type III R-M systems. Sequence analysis of this system in 22 non-typeable H.influenzae isolates revealed a hypervariable region in the central portion of the mod gene whereas the res gene was conserved. Maximum likelihood (ML) analysis indicated that most sites outside this hypervariable region experienced strong negative selection but evidence of positive selection for a few sites in adjacent regions. A phylogenetic analysis of 61 Type III mod genes revealed clustering of these H.influenzae mod alleles with mod genes from pathogenic Neisseriae and, based on sequence analysis, horizontal transfer of the mod–res complex between these species. Neisserial mod alleles also contained a hypervariable region and all mod alleles exhibited variability in the repeat tract. We propose that this hypervariable region encodes the target recognition domain (TRD) of the Mod protein and that variability results in alterations to the recognition sequence of this R-M system. We argue that the high allelic diversity and phase variable nature of this R-M system have arisen due to selective pressures exerted by diversity in bacteriophage populations but also have implications for other fitness attributes of these bacterial species

Curtis\u27s botanical magazine.

v.136=ser.4:v.6 (1910) [no.8292-8351

Curtis\u27s botanical magazine.

v.142=ser.4:v.12 (1916) [no.8642-8691

Curtis\u27s botanical magazine.

v.130=ser.3:v.60 (1904) [no.7932-7991

Curtis\u27s botanical magazine.

v.145=ser.4:v.15 (1919) [no.8786-8829

Differential improvements in lipid profiles and Framingham recurrent risk score in patients with and without diabetes mellitus undergoing long-term cardiac rehabilitation.

OBJECTIVE: To determine whether lipid profiles and recurrent coronary heart disease (CHD) risk could be modified in patients with and without diabetes mellitus undergoing long-term cardiac rehabilitation (CR). DESIGN: Retrospective analysis of patient case records. SETTING: Community-based phase 4 CR program. PARTICIPANTS: Patients without diabetes (n=154; 89% men; mean ± SD age, 59.6 ± 8.5y; body mass index [BMI], 27.0 ± 3.5 kg/m²) and patients with diabetes (n=20; 81% men; mean age, 63.0 ± 8.7y; BMI, 28.7 ± 3.3 kg/m²) who completed 15 months of CR. INTERVENTIONS: Exercise testing and training, risk profiling, and risk-factor education. MAIN OUTCOME MEASURES: Cardiometabolic risk factors and 2- to 4-year Framingham recurrent CHD risk scores were assessed. RESULTS: At follow up, a significant main effect for time was evident for decreased body mass and waist circumference and improved low-density lipoprotein cholesterol (LDL-C) level and submaximal cardiorespiratory fitness (all P<.05), showing the benefits of CR in both groups. However, a significant group-by-time interaction effect was evident for high-density lipoprotein cholesterol (HDL-C) level and total cholesterol (TC)/HDL-C ratio (both P<.05). TC/HDL-C ratio improved (5.0 ± 1.5 to 4.4 ± 1.3) in patients without diabetes, but showed no improvement in patients with diabetes (4.8 ± 1.6 v 4.9 ± 1.6). CONCLUSIONS: We showed that numerous anthropometric, submaximal fitness, and cardiometabolic risk variables (especially LDL-C level) improved significantly after long-term CR. However, some aspects of cardiometabolic risk (measures incorporating TC and HDL-C) improved significantly in only the nondiabetic group

Curtis\u27s botanical magazine.

v.62=ser.2:v.9 (1835) [no.3374-3457

Curtis\u27s botanical magazine.

v.34=no.1374-1418 (1811